1. Field of the Invention
The invention relates to an operation microscope, particularly to an operation microscope wherein the observation optical system and the recording optical system are improved with respect To an observation objective.
2. Description of the Prior Art
Referring to FIG. 1 illustrating the prior art, problems thereof will be explained.
An operation microscope 20 illustrated in FIG. 1 includes a tube 22 equipped with an objective lens 21 at its lower end, an illumination optical system 23 attached to the tube 22, an eyepiece tube 24 attached to the tube 22 in its upped portion and a decoding optical system 27 attached to the tube 22 at its side wall comprising a relay lens system 25 for a TV camera and a TV camera 26.
Within the above-described tube 22, there are arranged a variable power optical system 28 for providing an a focal variable power for an observation image above the objective lens 21, an image forming lens 29 and an erect prism (Dachprisma) 30 respectively.
Also, in the eyepiece tube 24 there are arranged a reflection prism 31 for reflecting light from the aforementioned erect prism 30, a total reflection prism 32 and an eyepiece lens 33.
Optical elements from the variable power optical system 28 to the eyepiece lens 33, inclusive, constitute the observation optical system 34.
The illumination optical system 23 comprises a light source La, such as a halogen lamp, a condensing lens 40 and a reflection mirror 36, Light from the light source La is thus collected by a condensing lens 40 and then reflected to an objective lens 21 by means of the reflection mirror 36, so that an observation objective 0 is irradiated with the light through the objective lens 21.
The above-described recording optical system 27 comprises a relay lens system 25 for a TV camera attached to the tube 22, a TV camera 28, a variable power optical system 37 for introducing selected light from the objective lens 21 to the relay lens system 25 for a TV camera and a mirror 38. An optical axis C.sub.1 of this recording optical system 27 is disposed at a position opposite to an optical axis C.sub.2 of the illumination optical system 23 with an optical axis C.sub.0 of the observation optical system 34 as the center.
In the case of an operation microscope 20 as illustrated in FIG. 1, when the object 0 for observation is located at the bottom of a deep hole, such as the interior of an ear, as shown in the figure, the light path for the recording optical system 27 is obstructed by the deep hole due to the angular spread between the optical axis C.sub.1 and an optical axis C.sub.2 of the illumination optical system. There thus arises a problem in that recording by a TV camera 26 becomes impossible,